Engineered practices of adobe masonry production in Ziway, Ethiopia
A non-engineered production practice of adobe-blocks prevails in southern Ethiopia around Ziway, which are used for rural housing. These blocks have a compressive strength of less than 1 MPa and exhibit deformed shape due to excess water and non-uniform distribution of teff straw during mixing. The objective of this research was to advocate a better practice to enhance the strength of adobe masonry unit. Tests were conducted on the soil samples for its suitability to produce adobe masonry units. Pumice aggregate and teff straw were used as additives. Compressive and flexural strength values observed for brick size specimens with 9% of pumice aggregate and 0.4% of teff straw content were 2.6MPa and 0.36MPa respectively. These values have passed the minimum requirement of California Building Code which is considered as standard for the present research. Whereas block size specimens showed compressive strength values less than the minimum requirement. Hence brick size was recommended to use in practice, over block size. Unit cost was considered affordable as the cost of pumice and teff straw used per unit was extremely low in value. Also around 60% cost reduction was observed when adobe units were used instead of Hollow Concrete Blocks for masonry construction.
Keywords: adobe block, adobe brick, masonry unit, pumice aggregate, teff straw